package com.netty;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpRequest;

/**
 * 创建自定义助手类：对于请求来讲，其实相当于入站，入境
 */
@Slf4j
public class CustomHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, Object o) throws Exception {
        // 获取channel
        Channel channel = channelHandlerContext.channel();

        if (o instanceof HttpRequest) {
            // 显示客户端的远程地址
            log.info("客户端地址=" + channel.remoteAddress());

            // 自定义发送的数据消息
            ByteBuf byteBuf = Unpooled.copiedBuffer("Hello netty~", CharsetUtil.UTF_8);

            // 构建一个http response
            DefaultFullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, byteBuf);
            // 为响应增加数据长度和类型
            response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain");
            response.headers().set(HttpHeaderNames.CONTENT_LENGTH, byteBuf.readableBytes());

            // 把相应刷新到客户端
            channelHandlerContext.writeAndFlush(response);
        }
    }

    @Override
    public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。注册");
        super.channelRegistered(ctx);
    }

    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。移除");
        super.channelUnregistered(ctx);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。活跃");
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。不活跃");
        super.channelInactive(ctx);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。读取完毕");
        super.channelReadComplete(ctx);
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        log.info("用户事件触发...");
        super.userEventTriggered(ctx, evt);
    }

    @Override
    public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
        log.info("channel。。。可写更改");
        super.channelWritabilityChanged(ctx);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        log.info("捕获到异常");
        super.exceptionCaught(ctx, cause);
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        log.info("助手类添加");
        super.handlerAdded(ctx);
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        log.info("助手类移除");
        super.handlerRemoved(ctx);
    }
}
